Hardline Islamic insurgent groups in Iraq are targeting a new type of victim with the full protection of Iraqi law, The Observer can reveal. The country is seeing a sudden escalation of brutal attacks on what are being called the 'immorals' - homosexual men and children as young as 11 who have been forced into same-sex prostitution.

There is growing evidence that Shia militias have been killing men suspected of being gay and children who have been sold to criminal gangs to be sexually abused. The threat has led to a rapid increase in the numbers of Iraqi homosexuals now seeking asylum in the UK because it has become impossible for them to live safely in their own country.

Ali Hili runs the Iraqi LGBT (Lesbian, Gay, Bisexual, Transgender) group out of London. He used to have 40 volunteers in Iraq but says after recent raids by militia in Najaf, Karbala and Basra he has lost contact with half of them. They move to different safe houses to protect their identities, but their work is incredibly dangerous.

Eleven-year-old Ameer Hasoon al-Hasani was kidnapped by policemen from the front of his house last month. He was known in his district to have been forced into prostitution. His father Hassan told me he searched for his son for three days after his abduction, then found him, shot in the head. A copy of the death certificate confirms the cause of death.

Homosexuality is seen as so immoral that it qualifies as an 'honour killing' to murder someone who is gay - and the perpetrator can escape punishment. Section 111 of Iraq's penal code lays out protections for murder when people are acting against Islam.

'The government will do nothing to tackle this issue. It's really desperate when people get to the stage they're trading their children for money. They have no alternatives because there are no jobs,' Hili says.

Graphic photos obtained from Baghdad sources too frightened to identify themselves as having known a gay man, and seen by the Observer, show other gay Iraqis who have been executed. One shows two men, suspected of having a relationship, blindfolded with their hands tied behind their backs - guns at the ready behind their heads - awaiting execution. Another picture captured on a mobile phone shows a gay man being beaten to death. Yet another shows a corpse being dragged through the streets after his execution.

One photograph is of the mutilated, burnt body of 38-year-old Karar Oda from Sadr City. He was kidnapped by the Badr Brigade in mid-June. They work with the Ministry of Interior and are the informal armed wing of the Supreme Council of Islamic Revolution in Iraq, who make up the largest Shia bloc in the Iraq parliament. Oda's family were given an arrest warrant signed by the Ministry of Interior which said their son deserved to be arrested and killed for immorality as a homosexual. His body was found ten days later.

Dr Haider Jaber is currently seeking asylum in the UK after fleeing Iraq in 2004. He says the abuse started to escalate in his neighbourhood after the invasion. One night, walking home from work, he was surrounded by five men, who told him he had to become a heterosexual Muslim. He says they abused him for wearing jeans and a T-shirt with English writing, and told him he should adopt traditional robes. As a crowd gathered to watch, he was then beaten and kicked to the ground.

The threats continued. Armed militiamen broke into his family home and then his workplace looking for him. Jaber finally left the country in April. His partner, Ali. was not so lucky. Jaber learned of his Ali's murder a few days after leaving Iraq. 'They didn't send the body to the family to have a grave or a flower garden. They said he didn't deserve it because he was an animal,' he said.

Ibaa Alawi has also fled Iraq. A former employee at the British embassy in Baghdad, Alawi met Tony Blair on one of his surprise visits to Iraq. He said Blair was concerned about the safety of the Iraqis working there and praised their bravery. 'Tony Blair said the British government was thankful for our efforts and knew we were putting our lives at risk working for the British embassy in Baghdad.'

Alawi is upset the same government is not willing to help him out. He believes the Home Office will refuse him asylum because it would have to face up to the level of chaos in Iraq, and how much influence is being waged by radical Islamists - and face the fact that, for some, there is still no freedom in Iraq.

· Jennifer Copestake's film on homosexual executions in Iraq will be shown on More4 News on August 7 at 8pm